Process for treating fibrous materials and resulting products



United States Patent Ofitice 3,234,043 Patented Feb. 8, 1966 3,234,043 PROCESS FOR TREATING FllBROUS MATERIALS AND RESULTING PRQDUCTS Edward L. Patton, Middlesex, N..l., and Robert J. Solari, Charlotte, N.C., assignors to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Sept. 11, 1961, Ser. No. 137,025 6 Claims. (Cl. l17139.4)

This invention relates to the treatment of fibrous materials. More particularly, the invention relates to an improved process for treating cellulosic fibrous materials, such as cellulosic textile materials, to impart wet crease recovery thereto.

Specifically, the invention provides a new and improved process for treating cellulosic fibrous materials, and particularly textile materials, such as cotton fabrics, to impart high wet crease recovery without unduly affecting loss of strength. This process comprises treating the fibrous material with caustic and an epihalohydrin or material which liberates epihalohydrins, and at some time during the process treating the fibrous material with a reducing agent and preferably sodium hydrosulfite or sodium borohydride. The invention further provides fibrous materials having improved properties which are prepared by the above-described process.

Nitrogenous resins have been applied to cellulosic textile materials to produce wash-and-wear fabrics. These resins, however, lack the ability to produce an acceptable wet crease recovery. Thus, the conventional thermosetting resins impart a satisfactory appearance to fabrics which are tumble dried, but fail to eliminate Wrinkles when the fabrics are drip or line dried.

It has been found that fabrics having high wet crease recovery which are durable to repeated launderings can be obtained by treating the fabric with epichlorohydrin or glycerol dichlorohydrin. This technique, however, re sults in a considerable loss of strength to the fabric. This is not too significant for certain applications, but if the material is to be used in the manufacture of goods, such as shirts and blouses, it would be highly desirable if some way could be found to lessen the loss of strength by the above treatment.

It is, therefore, an object of the invention to provide a new process for the treatment of fibrous materials. It is a further object to provide a process for treating textile materials to impart high wet crease recovery without material loss of tensile strength. It is a further object to provide a method for treating cellulosic materials with epihalohydn'ns or materials which liberate epihalohydrins without unduly decreasing their strength. It is a further object to provide a method for treating cellulosic materials with epichlorohydrin without materially affecting tear and tensile strengths. It is a further object to provide a new and simple method for preparing cellulose textile materials having high wet crease recovery and little loss of strength. It is a further object to provide new fibrous materials having improved properties. These and other objects of the invention will be apparent from the following detailed description thereof.

It has now been discovered that these and other objects may be accomplished by the process of the invention which comprises treating the fibrous material with caustic and an epihalohydrin or material which liberates epihalohydrins, and at some time during the process treating the fibrous material with a reducing agent, and preferably sodium hydrosulfite or sodium borohydride. It has been found that this special technique avoids the abovedescribed difiiculties of the prior known process and gives a product having very high and durable crease recovery as well as reduction in loss of tear and tensile strengths.

Crease recovery values obtained by this method, for example, may run as high as or higher than 260 to 290, with the loss of strength being, for example, reduced to between about 15% to 34%, with the conventional loss being between 40 and 60%. Further advantage is also found in the fact that by utilizing the epihalohydrin or material liberating epihalohydrin in a vapor state, the process can be conducted with a very short cure cycle and the process can be employed on a continuous basis as described hereinafter.

The special additives to be employed in the process comprise those inorganic materials known as reducing agents. They act to reduce groups and/or as oxygen scavengers. While the role in the process is not clear, it may involve both reduction of functional groups and/or elimination of dissolved oxygen. Materials known as reducing agents will perform both functionals. Preferred material includes the alkali metal and alkaline earth metal salts of inorganic acids the anion portion of which contains a member of the group consisting of sulfur, boron and phosphorus. Particularly preferred agents are those which have oxygen in addition to the abovedescribed elements in the acid portion of the salt molecule. Examples of suitable agents include, among others, sodium hydrosulfite, potassium hydrosulfite, sodium and potassium hydrophosphite, sodium and potassium thiosulfate and sodium and potassium borohydride.

The above-described special additives are employed only in small amounts and preferably in amounts not greater than 5% by weight of the reaction mixture. Particularly preferred amounts vary'from about .0l% to 2% by weight. The amount of the additive applied to the cloth also varies within these ranges. The exact amount of the cloth will, of course, depend on the wet pick-up. For example, wet pick-up of of 0.1% solution will give 0.1 gram per 100 grams of cloth.

The above-described additive or additives may be applied to the fibrous material at any time during the process involving the treatment with caustic and the epi-. halohydrins or materials which liberate epihalohydrins. For example, the additive may be applied to the fibrous material and the resulting material treated with caustic and the epihalohydrin or material liberating the same, or alternatively the additive may be applied and then the treated material further treated with epihalohydrin or material liberating the same, or still further, the fibrous material may be treated with caustic, epihalohydrin or material liberating the same and then with the reducing agent, or still further, the fibrous material may be treated with epihalohydrin or material liberating the same and then with caustic and the reducing agent. The reducing agent may also be applied simultaneously with the caustic or epihalohydrin. The preferred operation is to add the additive to the caustic solution used to impregnate the textile material.

The technique of application may vary depending on the circumstance. If it is to be applied by itself, the reducing agent is preferably dissolved in water to the right concentration for proper add on as noted above, and then this solution is then used to impregnate, spray or otherwise treat the fibrous materials. In other cases, the additive may be added as such directly to the caustic or epihalohydrin solutions used in the impregnation oi the fibrous materials.

During the process, the fibrous material is impregnated with an aqueous caustic solution. The caustic employed is preferably sodium hydroxide but potassium hydroxide or other metal hydroxide may be utilized. The strength of the caustic solution may vary but preferred concentrations vary from about 1% to 25% by weight. The higher concentrations tend to give higher wet crease re- The preferred materials to be employed in the process include those textile materials containing at least 30% cellulosic materials and preferably those derived from cotton and rayon.

To illustrate the manner in which the invention may be carried out, the following examples are given. It is to be understood, however, that the examples are for the purpose of illustration and the invention is not to be regarded as limited to any of the specific materials or conditions recited therein.

The wrinkle recovery values reported in the examples were determined by the tentative method of test for recovery of textile fabrics from creasing, using the verticle strip apparatus, ASTM Designation D1295-53T (reported as sum of average warp and fill measurements), and the tensil strength values were determined by Instron Tensile Testing Machine, Federal Specification CCC-T-l9lb, Method 5100. All tests were carried out at 65% relative humidity and 70 F.

The wet crease recovery values were determined by soaking the fabric in water for 5 minutes and then blotting before testing.

Example I This example illustrates the superior results obtained by using the process of the invention for treating cotton print fabric.

(A) Bleached 80 x 80 count cotton print cloth was impregnated with a aqueous solution of NaOH containing 1.0% sodium hydrosulfite and 0.1% lauryl sulfate at a wet pick-up of 100% using a Morrison laboratory 3-r0ll padder. The sample was rolled loosely into an approximately 2" diameter roll, clipped on one end to hold in place and suspended in a reaction chamber containing hot refluxing vapors of epichlorohydrin for a period of from seconds to 2 minutes. Vapor temperature at the time of insertion was 248 F. and at the time of withdrawal was 252 F. The fabric was then rinsed in hot running tap water and hung at room temperature to dry.

The finished fabric had an excellent white hue and excellent drip drying properties. The wet crease recovery angles and the filling tensile strength are shown in the table below for each of the periods of exposure:

Wet Crease Filling Ten- Reaction Time (See) Recovery silo Strength Angle, De- (Pounds) grees (W+F) 0 (control) 145 43.8 15. 205 38. 3 263 33. 2 45. 282 30. 5 60. 299 25. 8 90 292 21. 1

(B) The above procedure was repeated with the exception that the 1.0% sodium hydrosulfite was omitted from the process. The percent loss in filling strength obtained in this case is shown below:

Bleached 80 x 80 count cotton print cloth was impregnated with a 10% aqueous solution of NaOH containing 1.0% sodium borohydride and 0.1% lauryl sulfate at a wet pick-up of 100% using a Morrison laboratory 3-roll padder. The sample was rolled loosely into an approximately 2" diameter roll, clipped 'on one end to hold it in place and suspended in a reaction chamber containing hot refluxing vapors of epichlorohydrin for a period of from 15 seconds to 2 minutes. The vapor temperature was 240 F. The fabric was then rinsed in hot running tap water and run at room temperature to dry.

The finished fabric had an excellent white 'hue and excellent drip-drying properties. The crease recovery angle and filling strengths are shown in the table below:

Wet Crease Filling Reaction Time (See) Recovery Strength,

Angle Pounds Example [11 Example I was repeated with the exception that the bottom fabric was impregnated with a 7.5% aqueous NaOH solution. Related results are obtained.

Example IV Example I was repeated with the exception that the cotton fabric was impregnated with a 5% aqueous NaOH solution before being subjected to the hot epichlorohydrin vapors. Related results are obtained.

Example V Example I was repeated with the exception that the impregnated'e'otton fabric was suspended in a heated chamber and the hot epichloroliydrin vapors were swept into the chamber and in contact with the suspended imp'regnated fabric. Related results are obtained.

Example VI Results equivalent to those shown in Example I are also obtained by continuoulsy and slowly (period in chamber of about 1 minute) drawing the impregnated fabric through a stainless steel chamber containing hot vapors of refluxing epichlorohydrin. In this case the fabrics were cured in a flat state in a continuous manner.

Example VII This example illustrates the use of the process of the invention for treating rayon fabric.

Rayon fabric was impregnated with a 5% aqueous solution of NaOH containing 1.0% sodium hydrosulfite at a Wet pick-up of about using a Morrison laboratory 3-roll padder. Samples of the Lrayon fabric were suspended in a reaction chamber containing hot refluxing vapors of epichlorohydrin for a period of about 2 minutes. Vapor temperature was about 250 F. The fabric was then rinsed in hot water and hung at room temperature to dry. The resulting fabric had excellent drip dry ing properties and little loss of strength.

Example VIII Example I is repeated using a fabric which was a blend of 70% cotton and 30% wool. Related results are obtained.

Example X Example I was repeated using epichlorohydrin vapor at 245 F. and a one minute cure cycle. The resulting product had a wet crease recovery angle of 299.

Example XI Example I was repeated using a concentration of aqueous NaOH of 2.5%. Related results are obtained.

Example XII Example I to VII and X are repeated with the exce. tion that the agent employed in place of the sodium hydrosulfite are as follows: potassium hydrosulfite, sodium thio- 7 sulfate, and potassium borohyd-ride and sodium hypophosphite. Related results are obtained.

Example XIII Example XIV The .procedure in Example -I is also varied to the extent that the cloth impregnated with the caustic and epir' chlorohydrin and then with an aqueous solution of the sodium hydrosulfite. Related results are also obtained.

We claim as our invention:

1. A process for treating cellulosic textile materials to impart drip dry properties thereto which comprises impregnating the textile material with an aqueous caustic solution containing from 0.01% to 5% by weight of sodium hydrosulfite and exposing for a period of from about 15 seconds to 5 minutes the resulting Wet impregnated material to hot vapors of a member of the group consisting of epihalohydrins and materials which liberate 1 epihalohydrins'in an alkaline medium.

2. A process for treating cellulosic textile materials to impart drip dry properties thereto which comprises impregnating the textile material with an aqueous caustic solution containing from 0.01% to 5% by weight of 50- dium borohydride and exposing for a period of from" about 15 seconds to 5 minutes the resulting wet impregnated material to hot vapors of a member of the group consisting of epihalohydrins and materials which liberate epihalohydrins in an alkaline medium.

3. A process for treating cellulosic textile materials to impart drip dry properties thereto which comprises im 8; pregnatingthe textile material with an aqueous caustic solution containing from .01% to 5% by weight of so-. dium hydrophosphite and exposing for a periodof from about 15 seconds to 5 minutes-the resulting wet impregnatedmaterial to hot vapors of a member of the group consisting ofepihalohydrins and materials which liberate epihalohydrins in an alkaline medium.

4. A process fortreating textile materials containing at least 40% by weight of a cellulosic material to improve the drip. dry properties which comprises impregnating the material withia 2.5% to 10% by weight aqueous NaOH solution containing 0.01% to 5% by weight of sodium hydrosulfite and then exposing the resulting wet impreg nated material to vapors oi e'pichlorohydrin foria period of:15 seconds to 5 minutes, removing the treatment ma terial, Washing and drying.

5. A process as in claim 4 wherein thetemperatures of the epichlorohydrin vapors varies. from about "240 F.

to 275 F.

6; A process as in claim 4 wherein the textile material 1 is impregnated with the-.NaOH solution at a temperature between 15 C. and 40 C.

References Cited by the Examiner UNITED STATES :PATENTS 1,863,208 6/ 1914 Schorger.

1,959,406 5/1934 Brooks 8 -1-16 2,967,787 1/ 1961 Murphy. 117--62.1- 2,985,501 5/1961- Gagarine 8-.116XR OTHER. REFERENCES General Chemistry, Deming, fifth ed. (pp. 320 and.

, 288 pertinent).

from the bottom-of page, 378 pertinent).

WILLIAM D. MARTIN, Primary Examiner.

IGSEPH B. SPENCER, RICHARD. D. NEVIUS,

Examiners;

Organic Cl1emistry,.Whitetnore,August 1937 (four lines 

1. A PROCESS FOR TREATING CELLULOSIC TEXTILE MATERIALS TO IMPART DRIP DRY PROPERTIES THERETO WHICH COMPRISES IMPREGNATING THE TEXTILE MATERIAL WITH AN AQUEOUS CAUSTIC SOLUTION CONTAINING FROM 0.01, TO 5% BY WEIGHT OF SODIUM HYDROSUSLFITE AND EXPOSING FOR A PERIOD OF FROM ABOUT 15 SECONDS TO 5 MINUTES THE RESULTING WET IMPREGNATED MATERIAL TO HOT VAPORS OF A MEMBER OF THE GROUP CONSISTING OF EPIHALOHYDRINS AND MATERIALS WHICH LIBERATE EPIHALOHYDRINS IN AN ALKALINE MEDIUM. 